In many mining, quarrying, sand and gravel or pulp and paper operations it is desirable to measure the amount of raw material, such as aggregate, gravel, ore, pulp etc. being processed or moved, in order to maximize production at the operation. In the past, this has been accomplished either by weighing the amount of material loaded into transport vehicles, such as trucks or railway cars or through the use of auto weigh feeders, belt scales, or load cells all based on the use of strain gauge load cells combined with high speed sensors to measure tonnage. This can be an expensive set up, requiring installation of new equipment, wiring and material testing for calibration for each piece of equipment to be monitored. To maintain accuracy the belt scales or load cells also require regular calibration and zeroing of cells.
In Automation Control the Belt Scale is the most widely used device to measure weight of material movement however these devices are installed as separate equipment on a conveying device. One example of such an apparatus, is the Siemens Miltronics MSI Single Idler conveyor belt scale with an Accumass BW100 Integrator. If a breakdown or error develops with the belt scale while the conveyor is operating then often the conveyor will continue to operate until a convenient time arrives to make a repair or adjustment with the scale with resulting loss of data.
There remains a need for a means of measuring the amount of material being processed or moved in an operation such as a quarrying or mining operation which is inexpensive, simple to setup and operate and to adapt to existing operations. There is also a need to know how efficient the operation is running i.e. each step in a quarry, mine or sand and gravel operation is designed to move a certain quantity of material daily at an hourly rate. At some steps in the operation, downtime may occur and if a record is measured of this downtime or “No-load”, then this becomes an area that can be improved to increase production. Ideally an operator wants the process to run at design production rates with minimum downtime to maximize production. This invention will provide the measurement tools at a low cost to achieve this goal. In addition if measurements are made at the conveyors coming off the primary and secondary crushers and at some key conveyors going to final stockpiles then these measurements can be used as a new method to compare blasting results.
The invention described herein is based on a new method to calibrate the device, which increases precision and includes new applications for the use of this device, which will help industry to become more productive. This invention is an improvement over an earlier application number JJ-11 384US(USA) and number JJ-384CA(Canada) by Steve McIassac who has worked with the current inventor to improve the accuracy and scope of this new invention over the earlier which focused on the lower cost version based on current readings. This invention is also an improvement over an earlier similar idea the KiloWate PT4 conveyor belt scale based on U.S. Pat. No. 3,942,625.